The general aim is to gain insight into embryonic human brain development, partly because of the need to provide a framework for understanding abnormalities of brain development which occur during the embryonic period and which are common and can be severe. The broad, long-term objectives are two-fold: (1) to acquire high resolution gene expression data for embryonic human brain that will permit comparison with equivalent data being generated for animal models, notably the mouse. This will provide molecular anatomical landmarks of embryonic human brain development to supplement existing standard anatomical landmarks. In addition it will permit an assessment of species differences (and similarities) in embryonic gene expression patterns, and provide a measure of just how far we can confidently extrapolate from animal models. (2) to establish an interactive graphical database of high resolution human embryonic brain gene expression patterns mapped onto an anatomical framework. This will involve: (i) 3-D reconstruction of electronically digitised 2-D expression images and of histological images in test samples, and referencing against 3-D reconstruction of anatomy in histological reference embryos, (ii) database design and operability issues.